Answer: Choice C
They should be blocked by pain resistance so the subjects are as similar as possible.
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Explanation:
The process of blocking in statistics is where we group up people in blocks, and each block is determined by a characteristic of some sort. In this case, we're grouping people up by pain resistance level. Those very resistant to pain will be in one group, while those who easily feel pain will be in another block, and so on. It might be effective to have a pain scale and sort people by that.
Blocking is done so that we eliminate unwanted variability. We are testing the effectiveness of the itching cream, so all we care about is if the itch reduces or not. We aren't worried about the levels of pain. However, it says that "Previous studies have shown the effects of treatment may vary based on a subject's pain resistance". So we group up the people by pain tolerance to help eliminate the variability of pain tolerance levels.
This is why choice C is the final answer.
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Extra info:
- Choice A is false because a person's name doesn't have anything to do with if the treatment works or not.
- Choice B is false because we weren't given any info to indicate it being true. It may be true, but we simply don't have enough info to confirm it.
- Choice C is false for similar reasons as choice B.
2x+5=x-8
-x on both sides
x+5=8
-5 on both sides
x=-13
Answer:
E.
simple random sample
Step-by-step explanation:
Simple random sample: Every member and set of members has an equal chance of being included in the sample. Random samples are usually fairly representative since they don't favor certain members.
Plug them in:
x + 5y = 18
x - 3y = 10
F. (1,13)
G. (13,1)
H. (-2,4)
J. (-2,-4)
1 + 5*13 = 18 is obliviously not true so that takes out the first option.
13 + 5*1 = 18 : This is true but we have to check the next one.
13 - 3*1 = 10 : This is also true so we know this is the answer. We don't really need to check the other 2 but u can if u want to.
Hope that helped :) <span />
